remainder

        # Numeric.remainder

(from ruby core)
---
    remainder(other) -> real_number

---

Returns the remainder after dividing `self` by `other`.

Of the Core and Standard Library classes, only Float and Rational use
this implementation.

Examples:

    11.0.remainder(4)              # => 3.0
    11.0.remainder(-4)             # => 3.0
    -11.0.remainder(4)             # => -3.0
    -11.0.remainder(-4)            # => -3.0

    12.0.remainder(4)              # => 0.0
    12.0.remainder(-4)             # => 0.0
    -12.0.remainder(4)             # => -0.0
    -12.0.remainder(-4)            # => -0.0

    13.0.remainder(4.0)            # => 1.0
    13.0.remainder(Rational(4, 1)) # => 1.0

    Rational(13, 1).remainder(4)   # => (1/1)
    Rational(13, 1).remainder(-4)  # => (1/1)
    Rational(-13, 1).remainder(4)  # => (-1/1)
    Rational(-13, 1).remainder(-4) # => (-1/1)